Chuck for holding tools and bars



C. H. CLARE.

CHUCK Fon HOLDING TooLs AND BARS.

APPLICATION FILED NOV. 13.1919.

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,-UNITED STATES PATEN'P'M'OFFICE.

CHARLESHENRY CLARE, F LOWER BROUGHTON, SALFORD, ENGLAND.

Specification of Letters Patent.

CHUCK FOR HOLDING TOOLS AND BARS.

Patented Mar. 22, 1921.

Application filed November 13, 1919. Serial No. 337,675.

To all whom t may concern;

Be it known that I, CHARLES Henny CLARE, a subject ot' the Kin of Great Britain and lreland, residing at Rent street, Lower cned on to the article being held as the chuck commences to rotate, and the greater the resistance to turning offered by the article so held, the more intense is the grip of the chuck.

My invention will be better understood on reference to the accompanying sheet of drawings, in which Figure l is a part sectional elevation of a chuck made according to my invention.

Fig. 2 is an outside elevation of same.

F ig. 3 is an elevation of a split sleeve which ts'inside the chuck.' v

`Fig. d is a plan view, and

Fig. 5 an underside plan view of same.

The same lett-ers refer to similar parts throughout the several views.

As the principle of construction involved in my improved chuck will be the same Whatever type of article is being held, for

the convenience in this description I Shall refer to such article as a'drill.

According to my invention the shank a of the chuck has a surrounding iange a1, an

' internal recess a2 tapped with a left hand screw thread, and a' portion a3 'below the fiange screwed externally-with a right hand thread.` Adapted to be vscrewed into the recess @fis a split sleeve b with a tapered end b1 and having saw cuts b2 extending for a portionof the length. The upper end of the sleeve J2 is screw'e'd with a left hand thread to engage with the tapped portion of the recess ah The sleeveb may have a.

taper or parallel bore, and if desired, the upper end may' be` closed in except for a flatsided slot b3 to engage with the flats formed on the end of a drill shank. It should be mentioned that the sleeve is in some cases fully open at both ends so that bars' or similar articles may be passed as far through as may be desired.

A nose c with au internal vconical or taperi chine, and in this connection it is very ing chamber c1 is threaded at its upper end to engage with the threads on the portion a3 of the shank ai. The outer face of the nose may be suitably knurled or may be formed with a series of fiats c2 to admit of being engaged by a Spanner or Wrench.

The manner of operating my improved chuck is as follows:

Assuming the shank of a drill to have been inserted within the mouth of theV nose c and passed up through theV sleeve b unt1l the flats on the end engage with the flat sided slot 3; on the drill being pressed y against the Work it has to operate on and the shank a rotated, in the direction indicated bythe arrow on F ig. l, the statical Jfriction between the drill and the Work is sufficient to keep the former stationary together with the split sleeve b; this being so, there is a relative movement between the thread on the sleeve and the -internal threads of the shank, with the result, that the tapered end b1 of the sleeve is brought into close contact with theinclined Walls of the nose c. This causes the sleeve to contract, by reason of the provision of the slits L? and tightly grip the drill shank, which is then carried around With the chuck. The greater the resistance offered bythe Work to the tool in cutting or boring, the more intense will be the grip which the chuck has experiment lthat itis not essential to .ha-ve a flat sided slot in the top end of the sleeve, as the grip-of the sleeve on the drill 'is quite suiicient lto hold it. By reason of this a parallel shank drill may be held so as 't0 project any desired distance from the mouth of the chuck. Y A

It will be understood that my improved chuck can be used either as an independent device, or form part of the spindle of a masuitable for turret lathes. g

.My improved chuck, by reason of its large grip ing power can hold parallel shank drills as effectively as (or more so than) morse taper chucks engaging morse taper shank drills and since parallel shank drills are much less expensive than morse taper shank drills, the'use of my improved chuck results in an economygI the cost of the drills used.

It should, however, be explained that where a threaded nose is employed the turn ing movement of the shank a, (during the period when the statical friction of the drill is being overcome, and the tapered end b of the sleeve b bears upon the internal conicall face e of the nose) causes the nose to rise upon the right hand vscrew threads on the portion a3 ot the shank and so` augment vthe rapid and eiiicient grip of the chuck upon the tool being held.

Having now described my invention what I claim as new and desire to secure by Letters Patent, is

A tool holding chuck, comprising a tubular shank provided interiorly and exteriorly thereof with opposibely directed threaded portions, a sleeve having a threaded portion for engaging the interior thread of the shank, and a nose engaging the exterior thread and encircling said sleeve and adapt-- ed to engage the same upon rotation of the sleeve relatively to the shank.

In testimony whereof I have signed my name to this specification.

CHARLES HENRY CLARE. 

